1. Field of the Invention
The present invention relates to an image pickup unit for endoscope in which an image pickup device and a circuit substrate are connected to each other with leads extended from the circuit substrate.
2. Description of the Related Art
In order to observe a site such as inside a living body or structure, which is difficult to be observed, endoscopes have been used in medical and industrial fields, for example, and such endoscopes are configured to be able to be introduced from outside to inside of a living body or structure and include an image pickup unit for picking up an optical image.
An image pickup unit for endoscope includes an objective lens that forms an image of an object, and an image pickup device which is disposed on the image-forming surface of the objective lens and generally called as CCD (charge coupled device), CMOS (complementary metal oxide semiconductor) sensor, or the like.
For example, Japanese Patent Application Laid-Open Publication No. 2008-177701 discloses the image pickup unit for endoscope in which an image pickup device and a circuit substrate disposed on the rear face side of the image pickup device are electrically connected to each other with conductive leads. The leads are extended from the front end portion of the circuit substrate and bonded to electrode pads formed on the front face of the image pickup device on which a light-receiving portion is provided.
In the technique disclosed in the Japanese Patent Application Laid-Open Publication No. 2008-177701, the front end portion of the circuit substrate is protruded more forward than the rear face of the image pickup device on the outside of the side face of the image pickup device, to bring the electrode pads close to the front end portion of the circuit substrate.